try capelas the tacstar shotgun torch its under hunting and military tactical enharnsements i have mine mounted to the left of the bayonet boss on my styer but you could put it on a scope well depending on how fat your scope is but its better on the barrel
If you're using a 1" bodied scope you can use the mount in the link below to mount a Mini MagLite (2AA cell) to your scope. I'm using one on my Tasco 3-9x32 scope. I use a pressure switch purchased from e-Bay to activate the light when needed.